When one of our kids approached me to tell me that he and some of his class mates were planning to give a presentation about Dromaeosauridae (colloquially also known as "raptors"), he casually mentioned that they would also need some dinosaur masks for reenacting a pack of hunting deinonychuses.
After some feeble ad hoc attempts to manually design cardboard dinosaur mask cut-out sheets, I decided the time had finally come to learn how to operate the marvelous open source 3D modelling software Blender so that I could calculate polygon edge lengths and angles from the 3D model's vertex coordinates.
Guess how happy I was when I learned that Blender features right out-of-the-box a plugin capable of exporting 3D models as full-fledged cardboard cut-out sheets!
Since our printer is not capable of handling paper larger than A3, some manual post-processing of the PDF files generated by the cutout export script was required. I used Inkscape for splitting the the cutout shapes into multiple parts each of which would fit onto one quarter of an A1 page. To this end, I of course had to draw some additional glue seams.
The resulting A1 pages were each converted into multi-page A3 documents using the
pdfposter -m a3 -p 2x2a3 A1-input.pdf A3-output.pdf
The masks turned out rather large; you might wan to scale them down to 80 - 90% when printing.
Of course, the dinosaur masks presented here do not really represent accurate scientific reconstructions. I did try, though, to ensure that their shapes and colorization do indeed make sense in biological terms.
Tenontosaurus, a member of the Iguanodontia clade, is known to be preyed upon by deinonychus. The mask captures the following aspects of tenontosaurus biology:
- The long, narrow skull ends in a toothless, keratinaceous beak most suited for cropping plant parts.
- Just as it is the case with many of today's ungulates and other animals which are typically hunted by predators, tenontosaurus's eyes were located laterally, resulting in an almost 360° field of view. This enabled tenontosaurus to easily detect predators trying to close in from behind.
- Just like modern lizards and birds, dinosaurs probably didn't have auricles. Their tympani might have been right visible.
- Tenontosaurus lived in a landscape featuring floodplain forests and swamps with alternating light and shadowy patches. It is reasonable to assume that tenontosaurus was camouflaged by a skin pattern also exhibiting alternating dark and light dots and/or stripes in brownish and/or greenish tints.
- From melanosomes found in fossilized dinosaur skin and feathers we know that, just like many recent animals, dinosaurs frequently exhibited what is known as counterstaining: a dark back and a light belly. Since natural illumination is usually directed from the sky downwards, a counterstained animal's back becomes lighter and its belly darker, rendering its whole body rather flat and two-dimensional, thus making it harder to be discovered by predators.
- Animals frequently being preyed upon often disguise the location of their eyes by hiding them inside dark spots or stripes, thus making it more difficult for predators to selectively target their head, neck and/or throat.
The following aspects of deinonychus biology were taken into account when designing this mask:
- Like most dromaeosaurids, deinonychus featured a triangular-shaped skull with long jaws.
- Deinonychus's eyes looked forward, probably enabling three-dimensional vision.
- While most of deinonychus's body was probably covered with feathers, its snout was most likely naked, displaying scaled skin.
- No tympani where visible since they were hidden under plumage.
- Not just for prey, but also for predators it is useful to be camouflaged. Hence we applied a dotted/striped pattern onto the deinonyhcus mask, just like we did with the tenontosaurus mask.
- In particular the predator's eyes are well hidden inside a dark stripe, further dissolving its body shape.